new picture of earthrise taken by japanese probe
- Thread starter watermelony2k
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Thanks for that link.
Is it my imagination or does Earth look smaller from the moon than the moon looks from Earth?
What's the size difference between the two bodies?
It also amazes me that at seeing just how small Earth looks, how Earth can keep the moon in orbit that far away. Although I do know that the moon is slowly drifting further and further away. So in essence, the Earth really isn't... and so when the day comes the Earth loses its grip on the moon, this planet is in for some major changes in climate, especially when dealing with tides.
What's the size difference between the two bodies?
It also amazes me that at seeing just how small Earth looks, how Earth can keep the moon in orbit that far away. Although I do know that the moon is slowly drifting further and further away. So in essence, the Earth really isn't... and so when the day comes the Earth loses its grip on the moon, this planet is in for some major changes in climate, especially when dealing with tides.
Moon's radius is slightly over 27% of Earth's while its mass is about 1.2% of Earth's.
Yes the moon is drifting to a higher orbit because Earth is constantly transfering some of its own angular momentum to the moon's orbital angular momentum due the gravity gradient effect. However I wouldn't describe it as "Earth can't keep its moon in orbit". For one thing the momentum transfer is going very slowly so the moon is only moving out at a rate of about 40 mm per year. At the same time our day is increasing at rate about 2 microseconds (upper bound) per year. Even assuming the rate of change is constant then after about 1 billion years the moon would be only 40,000 km farther away or about 10% of its current distance from Earth.
Off top of my head when Earth's rotational rate matches moon's orbital angular rate the Sun would've long became a red giant. The entire earth-moon system would be well toast .
ancient said:
Daedalus12 said:
Off top of my head when Earth's rotational rate matches moon's orbital angular rate the Sun would've long became a red giant. The entire earth-moon system would be well toast .
No, it won't take anywhere near that long. It's slow, but not that slow.
Are you sure? The newer data seem to confirm that it'll take very long. Certainly longer than a few billions years.
Daedalus12 said:
ancient said:
Daedalus12 said:
Off top of my head when Earth's rotational rate matches moon's orbital angular rate the Sun would've long became a red giant. The entire earth-moon system would be well toast .
No, it won't take anywhere near that long. It's slow, but not that slow.
Are you sure? The newer data seem to confirm that it'll take very long. Certainly longer than a few billions years.
Well, I don't feel like digging for my stuff on this, but I am pretty sure, yeah. This much I do remember:
When the Moon’s orbit stabilizes:
1. It’ll be in geosynchronous orbit - fixed orbit
2. It’ll be about twice as small in our sky
3. The Earth day will stabilize at about 48 hours long. (or somewhere thereabouts)
So the tides will no longer be accelerating the Moon’s orbit, causing it to fly away, and the moon will no longer be pulling backwards on the Earth’s rotation, trying to catch the tidal bulge. Everyone will be happy.
As to how long this will take, I don’t recall, so I could be wrong about that. But it was my impression it wasn’t 1B yrs.
Anyway, it's a nice picture. I think I can see my house.
Groovy, gnarly, and radical
DontFeedPhil
Fleet Captain
Wow,
Someone musta changed the link. Because those pics looked like crappy computer generated shit. It didnt even look as good as what the US government made up back in the late 60's. And its weird how the clouds never change for the whole earthsetting. Must have happened withing 5 minutes.
I call shenanigans!!!
Someone musta changed the link. Because those pics looked like crappy computer generated shit. It didnt even look as good as what the US government made up back in the late 60's. And its weird how the clouds never change for the whole earthsetting. Must have happened withing 5 minutes.
I call shenanigans!!!
i think we've become too used to seeing blurry images of space from the 60's. Perhaps this is what new images will continue to look like.
That is a cool picture. But I thought the earth would look bigger from the moon, considering the way we can see the moon from here and the actual size???
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